Prep the chicken: Pat the chicken dry and cut into bite-size pieces. Dry chicken browns better and won’t steam in the pan.
Make the marinade: In a bowl, whisk gochujang, gochugaru (if using), soy sauce, rice vinegar, honey, sesame oil, garlic, and ginger until smooth.
Marinate: Add chicken to the bowl and toss to coat evenly. Let it sit for at least 20 minutes at room temp, or up to 8 hours in the fridge.
Heat the pan: Set a large skillet over medium-high heat and add the neutral oil.
When it shimmers, it’s ready.
Sear in batches: Add chicken in a single layer without crowding. Cook 3–4 minutes per side until browned and mostly cooked through. Transfer to a plate and repeat with remaining chicken.
Make it saucy: Lower heat to medium.
Pour remaining marinade into the pan with 1/3 cup water. Simmer 1–2 minutes, scraping up browned bits.
Thicken (optional): Mix cornstarch with 1 tablespoon cold water. Stir into the pan and simmer 30–60 seconds until glossy.
Finish: Return chicken to the pan and toss in the sauce for 1–2 minutes until coated and cooked through.
Adjust seasoning with a splash of soy for salt or a drizzle of honey for sweetness.
Serve: Top with green onions and sesame seeds. Spoon over rice or noodles, or wrap in crisp lettuce leaves for a lighter option.